title: The effect of fetal mesencephalon implants on primate MPTP-induced parkinsonism. Histochemical and behavioral studies.
abstract: Parkinsonism or hemiparkinsonism was induced by administration of 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine (MPTP) in four rhesus monkeys, which then received homologous fetal mesencephalon implants into the caudate nuclei. Cavities were prepared in the medial caudate nucleus 2 to 5 weeks before the fetal grafts were implanted. Control studies were conducted in unoperated MPTP-treated animals. Significant behavioral improvement, which occurred within weeks of implantation of fetal mesencephalon, was sustained for up to 7 months. No recovery was seen in the unoperated control animals. Histological examination revealed numerous surviving tyrosine hydroxylase (TH)-immunoreactive cell bodies. In addition to the graft, abundant TH-immunoreactive fibers were observed in the host caudate nucleus ventral to the region of the implanted and the nonimplanted cavities. Since TH-immunoreactive cell bodies of the substantia nigra compacta (A-9 cells) were destroyed by MPTP treatment and the ventral tegmental area (A-10) remained intact, it is concluded that sprouting of remaining host dopaminergic fibers occurs. These newly formed fibers appeared to emanate from the mesolimbic projection to the striatum. It is likely that the newly sprouted dopaminergic fibers account for the motor improvement elicited by precavitation and fetal mesencephalon implantation. These results suggest that the mechanism of recovery of parkinsonian primates after implantation of fetal dopaminergic tissue into the caudate nucleus is by stimulation of sprouting from host neurons. They also suggest that, with identification of the factors responsible for the formation of the new dopaminergic neuronal processes and with further development, tissue implantation may be an effective therapy for Parkinson's disease in humans.
authors.affiliation: CNS Implantation Unit, National Institute of Neurological Disorders and Stroke, Bethesda, Maryland.
authors.forename: K S
authors.initials: KS
authors.lastname: Bankiewicz
authors.forename: R J
authors.initials: RJ
authors.lastname: Plunkett
authors.forename: D M
authors.initials: DM
authors.lastname: Jacobowitz
authors.forename: L
authors.initials: L
authors.lastname: Porrino
authors.forename: U
authors.initials: U
authors.lastname: di Porzio
authors.forename: W T
authors.initials: WT
authors.lastname: London
authors.forename: I J
authors.initials: IJ
authors.lastname: Kopin
authors.forename: E H
authors.initials: EH
authors.lastname: Oldfield
mesh_terms: D015632:1-Methyl-4-phenyl-1,2,3,6-tetrahydropyridine; D000818:Animals; D001345:Autoradiography; D002421:Caudate Nucleus / Q000378:metabolism / Q000601:surgery; D005260:Female; D005333:Fetus; D007150:Immunohistochemistry; D008252:Macaca fascicularis; D008253:Macaca mulatta; D008297:Male; D008636:Mesencephalon / Q000196:embryology* / Q000637:transplantation; D010302:Parkinson Disease, Secondary / Q000139:chemically induced / Q000378:metabolism / Q000601:surgery; D011597:Psychomotor Performance; D014184:Transplantation, Homologous
chemical_list: D015632:1-Methyl-4-phenyl-1,2,3,6-tetrahydropyridine